The use of tillage apparatus is well known, and various types of apparatus have been developed that are useful for one or more tasks.
As such apparatus has been developed and utilized, it has become evident that such apparatus could be improved, particularly for the many different tasks to be accomplished. It has been discovered, for example, that conventional tillage apparatus, such as disc harrows, disc cultivators and rotary hoes, have not proved to be entirely suitable for preparing ground for seeding where legumes are to be grown in established grass sod.
For growing legumes in established grass sod, the ground surface is often uneven or rocky and may have grass swards of differing thicknesses thereon. To prepare such ground for seeding or grassland renovation, it is desirable that the number of trips that an implement must make over such ground be held to a minimum in order to accomplish such tasks as tilling, seeding, cultipacking and spraying of herbicides. Hence, an implement capable of performing all of the various tasks in succession during a single pass over the ground was needed.
Such an implement would preferably be towed, since this allows the tillage apparatus to be disconnected from the tractor in order to release the tractor for other uses, and, when towed, the engine of the towing tractor is commonly utilized for power, as shown, for example, by the patent to Kaller, U.S. Pat. No. 2,957,529.
Responding to this need, apparatus has heretofore been developed having the capability for opening a furrow, depositing seed in the furrow, packing the seed and spraying chemicals on the planted area. Examples of such apparatus for carrying out some or all of the various tasks can be found, for example, in U.S. Pat. Nos. 2,685,243; 2,734,439; 3,491,709; 3,566,813; 3,568,613; 3,604,515; 3,611,956; 3,673,970; 3,701,327; 3,749,035 and 3,866,552.
Cutting of the sward and sod mat and provision of a furrow therein has, however, proved to be a continuing problem, at least in some instances, as well as the problem of packing the seed.
While packer wheel assemblies have heretofore been known and suggested, such assemblies have not been completely suitable for all applications, including providing a dual packer wheel unit and/or a unit providing satisfactory flexibility over the contour of the ground regardless of the depth of a cut furrow.